Use the online calculators as the most rapid method of calculating natural logarithms if you have access to the Internet. Such services are quite a lot online, but look for them through search engines is not necessary - some of the search engines themselves have calculators for the desired function. For example, you can use the calculators search engines Google or Nigma. Going to home page of any of these systems, type in the search box write the desired mathematical operations. For example, to calculate the natural logarithm of the number 0,489 type "ln 0.489". The separator between integer and fractional parts it is better to use a period, although Nigma understand correctly and the number with a comma separator.
Use a software calculator that is built into the Windows operating system, if Internet access is missing. You can open it via the main menu on the "start" button (section "All programs", subsection "Standard", section "Service", select "Calculator") or using the run dialog programs which is called by the key combination WIN + R. In the dialog you can enter the command calc and click the "OK"button.
Switch a running calculator in the more advanced mode. If you are using Windows XP or earlier, the desired mode will be called "engineering", and later versions (Windows 7 and Windows Vista) is "scientific." Item with the same name in any version of OS is posted under the "View" menu of the calculator.
Use the keyboard or UI buttons on the screen to enter a number, the natural logarithm of which to calculate. Then click the button labeled ln and the program will calculate and show the calculation result.